Climate and the Southern Pine Beetle in Atlantic Coastal and Piedmont Regions

This report describes a large-area model that relates temperature and precipitation data to changes in southern pine beetle outbreak intensity. The model first transforms monthly mean temperature and total precipitation data with principal component analysis, and then uses the resultant linear combinations to predict a percent coverage indicator in ten climatic districts in Atlantic Coastal and Piedmont regions. While the model usually correctly estimates the sign of the coverage change from the previous year, it usually underestimates the magnitude. However, the analysis indicates that substantial changes were estimated 1972, 1974, and 1977, the three years in which coverage figures change the most from the previous year. The principal components were calculated from a very reliable 48-year record, and then were statistically related to a county coverage record from 1960 through 1980. The resultant model is applicable to a larger region than is previously published work. Forest Sci. 30:143-156.